drm/exynos: fimd: actually disable dp clock

fimd_dp_clock_enable() was setting the always to enabled,
this patch fix this to actually use the value that is set to 'val'.
Reported-by: Emilio López <emilio.lopez@collabora.co.uk>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -871,7 +871,7 @@ static void fimd_dp_clock_enable(struct exynos_drm_crtc *crtc, bool enable)
 		return;
 
 	val = enable ? DP_MIE_CLK_DP_ENABLE : DP_MIE_CLK_DISABLE;
-	writel(DP_MIE_CLK_DP_ENABLE, ctx->regs + DP_MIE_CLKCON);
+	writel(val, ctx->regs + DP_MIE_CLKCON);
 }
 
 static const struct exynos_drm_crtc_ops fimd_crtc_ops = {